| 摘要 |
PURPOSE:To prevent a portion between a drain region and a substrate from generation of an inversion region, and to prevent the portion from generation of conduction at an MOS semiconductor device by a method wherein a shielding conductor is interposed at a portion on a well between the drain region and the substrate to be crossed with a drain output signal line. CONSTITUTION:A shielding electrode 12 is formed on the surface of a field oxide film 6 on an n<-> type well 2 between a drain region 4 and a p<-> type semiconductor substrate 1 crossed on with a drain output signal line 10, and arbitrarily fixed electric potential between electric potential of the p<-> type substrate and electric potential of a source electric power source is applied to the shielding electrode 12 thereof. Accordingly, action as an MOST is the same as usual. When a negatively high voltage is applied to the drain output signal line 10, an electric field generated according thereto is shielded by the shielding electrode 12 not to reach a portion between the drain region 4 and the p<-> type semiconductor substrate 1, accordingly because the portion thereof is not inverted to a p type, conduction is not generated between the drain region 4 and the p<-> type semiconductor substrate 1. |
